For example, in a vehicle running test using a chassis dynamometer, as disclosed in Patent Literature 1, in order to assist test driver's driving, a vehicle speed pattern display apparatus is used. The vehicle speed pattern display apparatus is configured to display a prescribed speed pattern specified in regulations and the like and the allowable range of the prescribed speed pattern on a graph with one axis as time and the other axis as speed, as well as displaying the actual vehicle speed of a vehicle on the graph.
Meanwhile, in the above-described running test, even when a test driver's driving result falls within the allowable range, between when a test driver drives so as to trace the prescribed speed pattern and when the test driver intentionally drives so as to, for example, give priority to an improved fuel consumption within the allowable range, the test result is obviously different, and even without such intention, a variation in the test result may occur depending on a driver.
For this reason, for example, in SAE J2951, an index indicating a vehicle driving state in a running test (hereinafter referred to as a driving index), such as the deviation ratio between a prescribed speed pattern and an actual vehicle speed, is calculated and evaluated after the test, in order to reduce a driver-dependent variation in test result.
However, in SAE J2951, since the driving index is calculated and evaluated after the test, a driver cannot determine during driving whether the driver is driving within an allowable variation range. As a result, for example, when the driving index obtained after the end of the test exceeds the allowable range, it is necessary to perform the test again in order to reduce the variation in test result.